


Hibari's kitten

by Gingerspark



Series: Cat shifter Tsuna [1]
Category: Katekyou Hitman Reborn!
Genre: F/M, M/M, cat shifter tsuna, human hibari, reborn is very surprised
Language: English
Status: In-Progress
Published: 2018-07-07
Updated: 2018-07-07
Packaged: 2019-06-06 14:27:37
Rating: Not Rated
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,750
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/15196748
Author URL: https://archiveofourown.org/users/Gingerspark/pseuds/Gingerspark
Summary: Reborn was going to kill Iemitsu. Some oversights or errors in pre-job information packets were acceptable. Some were not. Omitting the fact that the subject of the report can turn into a cat was firmly on the unacceptable list.





	Hibari's kitten

**Author's Note:**

> So, this is going to be part of a series, and there's going to be a prequel covering bby Tsuna meeting baby Kyouya as a kitten and becoming friends (as a kitten), and the fallout from the sealing trapping Tsuna in human form.  
> But all you need to know is that kitten!Tsuna made friends with baby Kyouya, and never got round to shifting to human in front of Kyouya. Kyouya suspected his clever kitten might be a shifter, but wasn't going to push. Then his kitty vanished. Baby Kyouya was not happy.  
> Either way, things go pretty much as canon until reborn arrives, because Tsuna is trapped in human form and doesn't know why.

Reborn was going to _kill_ Iemitsu. Some oversights or errors in pre-job information packets were acceptable. Some were not. Omitting the fact that the subject of the report can turn into a cat was firmly on the unacceptable list. The kind of omission which meant he could go back to whoever hired him and tell them to stuff it, or at least demand an extortionate bonus.

For the head of an intelligence agency, not knowing that your own son can turn into a cat was a pretty big thing to miss. Reborn wondered what else the irritating (and apparently incompetent) man had missed as he dashed down the street in pursuit of his now cat-shaped student.

Reborn had had many expectations for the first time he shot his student with a dying will bullet. His best guess, given his knowledge of his student and his own prompting, was that Tsuna would run off (in his boxers because Reborn had to get his entertainment somewhere) to talk to Kyoko. That had all gone to hell in a handbasket the moment after the bullet had burned Tsuna’s clothes off. Reborn had several backup plans if his student acted against expectations, absolutely none of which accounted for Tsuna _turning into a cat_. A very fluffy adolescent cat.

He was having to use sun enhanced strength and speed, and he was still losing ground. Dying will mode cats were faster than dying will mode humans, who knew? Fortunately Tsuna was shedding flame traces everywhere, enabling him to follow his student up to the school roof.

He reached the roof a minute or so after Tsuna to find his student, still a cat, dying will flame burning on his forehead and under his paws, curled up asleep in the lap of a boy, who looked dazed and bewildered. Reborn hadn’t actually been aware it was possible to sleep in dying will mode, but it seemed his student was determined to subvert every expectation he had.

More importantly, those were some very cloudy looking sky flames, violet tongues flickering through the orange. And wasn’t that bizarre, his student didn’t act cloudy at all. A seal to prevent him from going active shouldn’t have changed any of his underlying personality trains unless- _damn you Timoteo_! He was sealed when he was already active. That was – _mio dio_ that explained so much. The clumsiness, the slowness, the anxiety. Although not the cat transformation or who the hell this boy way, and why Tsuna’s greatest regret was not - napping on him with his dying will? Or why Timoteo sealed an active sky, why Iemitsu let it happen to his own son, and why concerns were never raised about what was presumably a sudden change in ability and personality.

Reborn studied the boy, bringing up the information he knew. Hibari Kyouya, 15, head of the disciplinary committee, strong latent cloud. Rules Namimori middle with a pair of tonfa. Looking closer at the boy, he added ‘looks startlingly like a pre-curse Fon’ to his list. Hibari had shifted from his initial startled confusion to what decades of association with Fon told him was joyous awe. The boy was gently stroking the cat with obvious affection, careful not to wake him. Familiarity with Tsuna’s cat form, but according to both now doubtful reports and his own observations, not Tsuna himself.

All of this added up to a picture Reborn really, really didn’t like. Tsuna’s greatest regret, even when prompted to think about other things, was not spending more time with Hibari. As a cat. A cat Hibari apparently hadn’t seen in years. Tsuna was sealed as a young child. Hibari didn’t connect the cat and Tsuna.

Hoping his worst fears wouldn’t be confirmed, Reborn closed his eyes and gently reached out with his flames, careful not disturb the pair. He hung his head as he sensed the frayed ends of a guardian bond, half-formed and then broken. Already he could sense the loose edges of the bond weaving back together, stronger now Tsuna was flame active. Timoteo had sealed an active sky with a half-formed guardian bond. Reborn ruthlessly shoved down the surge of sympathy-horror-pity he felt at the thought of the two boys dealing with bond bereavement likely without even understanding what had happened, even leaving aside the catastrophic effects of sealing a flame active sky.

He had a situation to deal with, because the bullet would only loosen the seal for a few more minutes, and when that happened he would have two functionally civilian teenagers suffering from a broken bond for the second time. Both of whom were cloudy, one active but sealed, and one now teetering on the edge of activating as a pure, strong cloud. He pulled out a phone to call for backup, cloud containment was not his skillset. He needed a rain, one close enough to arrive before the school was demolished by angry teenage cloud.

“Hello, you’ve reached Takesushi-“

“I need rain backup on the roof of Namimori middle in about two minutes, imminent cloud rage” he snapped out as he jogged past the imminent disaster towards the stairwell. The ex-assassin had a son at this school, so would likely be willing to help out.

“Five minutes” came the terse reply as he was hung up on. Reborn stepped into the corridor and glanced around for the nearest fire alarm, drawing a gun and shooting it. As soon as the alarm rang out, he turned back to the rooftop and contemplated his options for containing a raging cloud _nonlethally_ until Yamamoto Tsuyoshi arrived. Hopefully evacuating the students who had already arrived would minimise civilian casualties and draw attention away from any flame use.

As he focused his attention back on the boy his heart sunk. That was Fon’s small smile, on a now flame active cloud with a full guardian bond. One minute and thirty seconds to go until the seal snapped that bond again. Reborn cursed Timoteo in his head as he watched the boy he suspected to be some relation to Fon pet Tsuna’s ears. This was going to be a disaster, he could tell. Not even a fun, chaotic disaster. A political mess of a disaster. How could Timoteo be so _stupid_.

Reborn pulled out his phone again and called Fon – he needed more information, if this boy was related to Fon and had a similar degree of early martial arts training, then that that would be a problem.

“Reborn?”

“Fon. It’s urgent. Relatives in Namimori?”

“How?” Fon’s voice had switched from his usual serenity to the calm that promised destruction.

“The boy looks like you, the cloud. How much training does he have, how do I contain him without killing him?” He’d explain the situation properly when he didn’t have a countdown to enraged cloud.

Thankfully Fon grasped the urgency of the situation.

“No flame training, skilled for his age in martial arts, not far behind me at that age, usually uses tonfa, Reborn what’s happening?”

“My new student is his sky, the seal will be back in place in under a minute, he went active and formed a full guardian bond while my student was shot with a dying will bullet. I’ve got rain backup on the way.”

Reborn heard a string of curses in cantonese before Fon switched back to Italian. “Reborn, you will do everything you can for my nephew until I get there.”

“Of course Fon.” Reborn hung up, knowing he was almost out of time.

He watched as the flame on the cat’s forehead and paws flickered and died, and the cat was suddenly replaced with a mostly naked teenager. Hibari looked shocked, eyes wide and jaw slack. Tsuna had woken up with a jolt as the seal snapped back into place, and was rubbing his eyes and looking around in confusion.

“HIIEEEEE!” Tsuna noticed he was undressed and sprawled across Hibari’s lap and scrambled backwards, stumbling to his feet. “S-s-sorry Hibari-san” he stammered before fleeing to the stairwell as Hibari gaped in shock.

Reborn stayed, hoping his student’s wariness of Hibari and the fire alarm would get him out of the school while he tried to mitigate whatever the cloud’s response would be. As his student fled, he watched Hibari’s face crumple into grief, a hand stretched out towards his student’s back.

He stepped forward before the boy could shift towards anger.

“Hibari” The boy ignored him. “Hibari, do you want to know what just happened?” Hibari’s eyes narrowed, focusing on Reborn’s small form.

“Infant.” There was a pause while Hibari seemed to struggle for words. “I thought my kitten was dead.” _My kitten._ Well, that would be something to mock Tsuna for later. When he didn’t have a cloud to placate.

“Your kitten wasn’t dead Hibari. He was trapped, and we’re going to fix things so you can spend time together whenever you both want.”

Hibari’s eyes narrowed, and Reborn sighed. He’d hoped the cloud wouldn’t focus on that part.

“Who trapped my kitten.” Hibari growled, eyes flickering violet as he pulled out his tonfa.

“It’s a complicated situation, and those responsible aren’t in Japan right now.”

Reborn jumped sideways as a tonfa cratered the rooftop where he’d been standing.

“Where are they?” Hibari’s tonfa were limned with violet flames.

Reborn raised an eyebrow, glancing meaningfully at the large hole in the roof. “Raging clouds don’t get information. Calm down.”

Reborn dodged again, bouncing around the rooftop, and carefully refrained from drawing a gun. Injuring his student’s cloud would be a bad idea, and shooting the boy with a dying will bullet an even worse one.

He could feel a strong rain getting closer, he only had to stall the boy for a few more seconds. Annoyed as he was at having to deal with a raging cloud, he was impressed with the strength of the cloud flames he could feel. His student had done well to draw in such a strong guardian, and once they fixed whatever damage a broken bond and years apart had done (damn Iemitsu to the deepest circle of hell) Tsuna and Hibari would be a force to be reckoned with.

Hibari was glaring furiously at him, striking out with his tonfa with speed and precision Reborn needed to use sun enhanced speed to avoid. Not that it was much of a challenge, talented and well trained as the boy was, he’d been flame active for under five minutes. Unless the boy figured out how to propagate his speed he didn’t have a chance in hell of hitting him. Unfortunately that meant a certain level of collateral damage, and the roof was pockmarked with craters and rubble.

Yamamoto Tsuyoshi burst out of the door, still dressed in his chef’s uniform and closely followed by a boy with a ridiculous hairstyle. Hibari turned towards the noise, then slowed as Tsuyoshi’s rain flames wrapped around him. The violet faded from his eyes, and he blinked slowly before slowly slumping to the ground. The boy who’d accompanied Tsuyoshi leapt forward with a cry.

“Chairman!” He knelt beside Hibari and frantically checked his pulse before aiming a suspicious glare at the two killers eyeing each other. “What did you do to the chairman?”

Tsuyoshi straightened up from where he’d been bent over panting heavily.

“I just calmed him down and sent him to sleep, he’ll be fine, he’s a strong boy.” Tsuyoshi said, glancing around at the destruction surrounding them and raising an eyebrow. “Very strong.”

**

Tsuyoshi looked between the sun arcobaleno, the unconscious Hibari boy and the disciplinary committee member fretting over him, and wondered what the hell had happened to get the boy flame active. He was very, very glad Takeshi didn’t seem to have been involved in whatever this was.

He smiled at the hitman and bowed. “It’s good to meet you. I’m Yamamoto Tsuyoshi”.

“Ciaossu, Yamamoto-san. Thank you for your assistance.”

He grinned, absentmindedly noting the disciplinary committee boy shrinking away from him. “It’s no trouble. This is my son’s school after all.” He tried to tone down the edge of threat in his grin, the poor boy looked stressed enough already.

“So, Reborn-san, what happened to upset Hibari-kun?” He knew Reborn would catch the implied ‘what did you do to send a cloud active and raging, and why did it happen at my son’s school?’

The hitman tipped his hat forwards. “It’s better discussed somewhere else.”

He nodded in acknowledgement, not around civilians then.

“I have a private training ground with a guesthouse, would that be suitable?” Tsuyoshi was not going back off, he needed to know what happened, and why the _sun arcobaleno_ was in Namimori and interacting with teenagers. “It’s remote enough that the boy can have privacy when he wakes up.”

“I’m coming with you.” The disciplinary committee boy states firmly, eyeing both of them suspiciously. “You’re not taking the chairman anywhere without me, not while he’s unconscious.”

“This doesn’t involve you.” Reborn states dismissively.

Tsuyoshi thinks about the backup that Kusa-something could call in as Hibari’s second, and quite how bad a middle aged man carrying an unconscious teenage boy off to a secluded place in the woods looks, and decides to take a different tack.

“Apologies for not introducing myself earlier, I was in a bit of a rush. I’m Yamamoto Tsuyoshi, pleased to meet you.”

“Kusakabe Tetsuya” the boy responds with a bow.

“Kusakabe-kun, I understand your concerns, but there are conversations Reborn-san and I need to have with each other and Hibari-kun in private. You can accompany us to the grounds, but we’ll likely need you to leave when he wakes up.”

Kusakabe hesitates for a moment, and then nods his head, gathering Hibari into his arms.

As they follow the teenagers through the emptied school, Reborn uses mist flames for something. He glances sharply at the arcobaleno.

“It’s just a privacy illusion. I need to check in on my student, could you take Hibari and keep him asleep until I get there? Vongola will ensure you’re compensated for the trouble.”

Vongola would? Well, that was interesting. Presumably the boy was a guardian candidate to this student of Reborns, and didn’t that have interesting implications. The heir to the vongola was in Namimori?

“Of course. I can likely manage another twelve hours or so.” He fished a scrap of paper and a pen out of his pocket and wrote down the location. “I don’t particularly want to draw attention leaving the school, could you- “

Reborn nodded, then vanished, leaving him to escort the two boys.

**

Tsuna was freaking out. Reborn had shot him! And then everything was a bit fuzzy, but he’d felt warm and whole and he’d shifted! After so many years, he’d finally shifted again. And he’d been with Hibari, and he’d felt safe and whole and _home_ for the first time in years. And then he was cold and alone again, (but not quite so much as he had been) and half-naked in Hibari’s lap. Hibari. Hibari saw him shift. Hibari probably hated him. Hibari was going to bite him to death for public indecency. Hibari knew, knew he was useless Tsuna, would he even want to be with him when he was a cat? Had he messed things up forever?

He’d been hiding in a broom cupboard hoping Hibari wouldn’t find him when the fire alarm had gone off. Then he’d realised he was in his boxers, and decided to stay. He’d figured he’d be less dead hiding during a fire than running around nearly naked during a fire chased by Hibari. The thuds and crunches were really worrying though, so he’d curled into a ball in the corner.

“Dame-Tsuna, you’re supposed to leave the building when the alarm goes off.” A voice came from above him.

“Hieeee! Reborn!” Oh god, Reborn saw him shift, Reborn knew, what was he going to do – ‘thwack’ something hit him on the forehead, and he looked up to see Reborn wielding a leon hammer.

After the Leon hammer vanished Reborn looked at him for a long moment, seeming… contemplative?

“I think we both have things to explain Tsuna.” Tsuna nodded in response to Reborn’s serious tone. “We’ll go back to your house.”

Tsuna hesitated. “Reborn, um… my clothes?” He didn’t want to walk home in his boxers!

“Clothes? You’re wearing clothes Dame-Tsuna.” Reborn turned on a heel and left the cupboard.

Tsuna glanced down to find himself suddenly dressed in his uniform again.

“Hieeee?” He scrambled after Reborn, bewildered.


End file.
